package com.mycompany.mvc.weixinUtils;

import com.mycompany.mvc.config.SystemConfig;
import com.mycompany.mvc.utils.SystemUtil;
import org.apache.commons.collections.MapUtils;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.util.Map;

/**
 * Created by Jintao_Ma on 2017/9/4.
 */
public class SignUtil {
    private static String weixinToken = SystemConfig.getProperty("weixinToken");

    /*验证签名*/
    public static boolean checkSignature(Map<String,Object> map) {
        String[] arr = new String[] {
                weixinToken,
                MapUtils.getString(map,"timestamp",""),
                MapUtils.getString(map,"nonce","")
        };
        /*将token、timestamp、nonce三个参数进行字典序排序*/
        Arrays.sort(arr);
        StringBuilder content = new StringBuilder();
        for (int i = 0; i < arr.length; i++) {
            content.append(arr[i]);
        }
        /*将三个参数拼接成一个字符串进行SHA-1加密*/
        MessageDigest md = null;
        String tmpStr = SystemUtil.Empty;

        try {
            md = MessageDigest.getInstance("SHA-1");
            byte[] digest = md.digest(content.toString().getBytes());
            tmpStr = byteToStr(digest);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        content = null;
        /*将sha1加密后的字符串可与signature对比，标识该请求来源于微信*/
        return (tmpStr != null) ? tmpStr.equals(MapUtils.getString(map,"signature","").toUpperCase()) : false;
    }

    /**将字节数组转换为十六进制字符串
     * @param byteArray
     * @return
     */
    private static String byteToStr(byte[] byteArray) {
        String strDigest = "";
        for (int i = 0; i < byteArray.length; i++) {
            strDigest += byteToHexStr(byteArray[i]);
        }
        return strDigest;
    }

    /**将字节转换为十六进制字符串
     * @param mByte
     * @return
     */
    private static String byteToHexStr(byte mByte) {
        char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
        char[] tempArr = new char[2];
        tempArr[0] = Digit[(mByte >>> 4) & 0X0F];
        tempArr[1] = Digit[mByte & 0X0F];
        String s = new String(tempArr);
        return s;
    }




}
